Molecular Control of Tiller Angle and Its Role in Rice Domestication

ABSTRACT Plant architecture is a key determinant of rice ( Oryza sativa ) productivity, with tiller angle playing a central role in optimizing plant density, light interception, and yield. During domestication, rice underwent a critical transition from the prostrate growth habit of wild relatives such as Oryza rufipogon to the erect architecture of cultivated varieties, driven by selection for reduced tiller angle. While numerous studies have identified genes associated with tiller angle regulation, a comprehensive synthesis integrating domestication genetics, physiological mechanisms, and emerging biotechnological approaches remains limited. This review provides a critical and integrative perspective on the molecular control of tiller angle, distinguishing between genes that directly regulate gravitropism and shoot orientation (e.g., PROG1 , TAC1 , LAZY1 ) and those that indirectly influence plant architecture through hormonal or developmental pathways (e.g., D3 , D14 , D53 , sd1 ). We highlight key domestication genes, including PROG1 , PROG7 , TIG1 , and the RPAD locus, and clarify the current status of BTA8 as a candidate locus associated with basal tiller angle whose molecular function and regulatory interactions remain unresolved. Importantly, we move beyond descriptive summaries to propose a conceptual framework linking gene regulatory networks, auxin‐mediated gravitropism, and evolutionary selection during domestication. We further evaluate how recent advances in multiomics, single‐cell technologies, and CRISPR/Cas‐based genome editing can address current bottlenecks in dissecting complex traits such as tiller angle. By integrating genetic, physiological, and technological perspectives, this review identifies key knowledge gaps and outlines future research directions, including network‐level analysis and precision breeding strategies. These insights provide a foundation for exploiting wild rice genetic diversity to develop climate‐resilient, high‐yielding cultivars with optimized plant architecture.